It's not necessarily over-priced at £8000. In effect, you are getting a new instrument for that price, as with the new strings, wrest plank and pins it will probably last about 100 years before it needs to have any other maintenance than tuning. Steinway, Bechstein, Bosendorfer and Bluthner were competing massively for business around the turn of the 20th century and they couldn't afford to allow a lapse in quality. Apparently Bechstein were churning out about 5000 pianos a year about that time. It's incredible to think that they maintained the standards that they did - there are loads and loads of >100-year-old Bechsteins still in daily use. What other area of manufacturing has maintained such widespread longevity, with hardly any significant improvements in that time? I can't think of one. Incidentally, you can buy a new Bosendorfer 130 upright (I think the 130 indicates the height in cm) for a cool £36k.
Bear in mind that my piano (I think it's a Model 3: 88 keys and 1891) still has the original wrest plank and, I think, pins. It's 126 years old. It was given a major overhaul when we bought it in 1978, but the ovalling of the pin holes dates back to its origin, I think. Marcus Roberts, who makes those really lovely geeky piano videos, talks about the later Bechsteins having wrest planks that hold their tuning rather better than the earlier ones. I gain the impression that your Model 8 would be the later, improved version of my Model 3. It's pretty hard to find any firm info on the internet though. I expect a phone call to Roberts themselves (I think I am going to have to have a trip to Oxford just for that purpose - and to play some of their pianos of course!) would clear the matter up in a few seconds.